The present invention relates to method of correcting defect of a pattern formed on an article substrate, such as a thermal head and a photomask which is used for forming fine patterns of a printed circuit board and a semiconductor device etc.
FIGS. 7 and 8 are a partial plan view of a surface of a photomask. FIG. 7 shows a missing or transparent detect 2 within a patterned Cr film 1 formed on a substrate. The missing defect 2 is defined as an incidentally lost part of the regular pattern and therefore is transparent on the photomask. FIG. 8 shows a remaining or oblique defect outside a regularly patterned Cr film 1 formed on the photomask substrate. The remaining defect 3 is defined as an incidentally left part of the film 1 other than the regular predetermined pattern.
FIG. 9 shows a partial plan view of a surface of a thermal head and FIG. 10 is a sectional view taken along line B--B of FIG. 9. The thermal head is comprised of a substrate 4 made of A.sub.2 O.sub.3, a heat-generating resistive element 5 formed of TaN on the substrate 4 and patterned electrodes 6 and 7 made of Cu and connected to the heat-generating resistive element 5. Each segment of the electrodes 7 has a width of 0.105 mm, and adjacent segments have therebetween a spacing of 0.02 mm. A missing defect 8 is incidentally caused on the patterned electrode 7, and a remaining defect 9 is incidentally caused between adjacent patterned electrodes 7.
There have been various conventional methods of correcting missing defects of pattern caused on a patterned article such as photomasks and thermal head elements. For example, a photoresist film is coated over the entire surface of the patterned article and a part thereof is removed by exposure and developing processes from an area corresponding to the missing defect. Thereafter, metals such as Cr and Cu are evaporated over the article to selectively deposit a metal film on the area of missing defect 2 or 8. This correction method is called evaporation method. In another method, ion beam or laser beam is irradiated onto the portion of missing defect 2 or 8 within medium of organic metal complex gas or organic metal gas to form a corrective film on the portion of missing defect 2 or 8. This ion beam or laser beam method is disclosed, for example, in Japanese Patent Publication Nos. 46055/1983 and 22372/1984 and in Japanese laid-open Patent Application No. 182726/1985.
There have been various conventional methods of correcting remaining defects caused on the patterned article. For example, a photoresist is coated over the entire surface of the article, and a part thereof is selectively removed by exposure and developing processes from an area corresponding to the remaining defect 3 or 9. Thereafter, the exposed remaining defect is etched and eliminated. This method is called etching method. In another way, ion beam or laser beam is selectively irradiated onto the remaining or left defect 3 or 9 to remove the same. This method is called ion beam or laser beam method.
However, in the evaporation and etching methods, coating, exposure and developing processes of photoresist film are required to thereby consume considerable amount of working time. Further, these additional processes may cause another subsidiary pattern defect. In the ion beam method, a patterned article to be corrected must be held in vacuum. The ion beam has a small beam spot, hence the considerable amount of correction time is consumed to correct a pattern defect which may have a dimension in the order more than several tens .mu.m. In addition, a correcting apparatus is expensive. In the laser beam method of correcting missing defects, the formed corrective film does not have sufficient adhesiveness to the substrate. Since utilized organic metal gas must be treated carefully, the correcting work is troublesome. The utilized correcting apparatus is expensive. Further, in the laser beam method of correcting remaining defects, the utilized correcting apparatus is expensive.